1. Field of the Invention
The invention concerns a process and a device for measuring angles in the horizontal plane.
2. Description of the Related Art
In order to determine the angle of tilt of an element with respect to the horizontal plane, generally use is made of gravity. For example, U.S. Pat. No. 4,707,927 discloses an inclination sensor, which measures its spatial tilt with respect to the horizontal plane by means of an electrically conductive fluid, which is enclosed in a spherical intermediate space, which is formed by a spherical common electrode and four opposing suitably shaped detecting electrodes. The liquid moves according to the angle of tilt of the sensor, thereby setting up electrostatic capacity between the electrodes, which is detected using readout electronics. Further, it is known from U.S. Pat. No. 4,716,534 to use a sensor for measuring the angular alignment of a reference surface in relation to the gravitational vector, using a rotatably mounted disk upon which a weight is mounted eccentrically to keep the disk in a relatively constant position relative to the gravitational vector, which disc is provided with graduated markings along the edge, which markings are electronically detectable, e.g. by a photodetector. This type of angular measurement is however not suitable to measure angles in the horizontal plane (angle of tilt). For this, it is necessary to employ optical measuring processes, for example involving a laser.